It is planned to study the mechanism and control of energy transducing processes in normal and tumor cells. Three ion pumps and several channels will be investigated. The proton translocating pump of mitochondria, the Ca 2 ion pump of sarcoplasmic reticulum, and the Na ion K ion pump of the plasma membrane are the ATP driven pumps that will be analyzed. Specific emphasis will be placed on examining the role of the proteolipids and to reconstitute the functional pumps with the minimal number of components required for function. Among the other ion transport systems that will be studied in the coming years are: the phosphate transporter of sarcoplasmic reticulum, the lactate transporter of Ehrlich ascites cells and the transport systems responsible for the uptake of Ca 2 ion into cells and into mitochondria. We plan to continue with studies of the reconstituted acetylcholine receptor. Further resolution of its components and investigations of the desensitization phenomenon are the primary objects in this research. The phospholipid requirements for the reconstitution of the acetylcholine receptor will also be explored.